Well, Jug was countered by SP - that was a valid and logical balancing.
In MW2 weapons are generaly weakened and hitzones tightened - M16 without SP can take up up to 3 bursts to score a kill (not perfectly lined shots).
So Jugg isn't needed in MW2.
If they add Jugg - I would agree that it have to slow the player down. I'm sure it won't be possible to have FMJ and Jugg at the same time.
Helis on MW2 are not a problem, as long as someone on the team has stingers. When I get hit by heli I switch to stinger loadup and blast it out (2 shots take PL down).
The problem is the Gunship - 3 rockets, so 2 ppl on the team must cooperate to take it down - but you all know how well that works in COD:))). I'd say they have to make it available after 12-15 kills.